Machine tools, such as turning machines, are used in manufacturing to machine workpieces by removing material from the surface of the workpieces. A new surface is thereby generated which conforms more closely to the desired final shape of the part. Conventional turning machines include a spindle rotatably mounted in a headstock which is fixedly mounted to the bed of the machine. A workpiece supporting means, such as a chuck, is used to securely support a workpiece on the end of the spindle during the machining operation. The spindle is driven by a motor and the rotating workpiece is brought into engagement with a nonrotating cutting tool so that the desired amount of material can be removed.
The workpiece and tool are moved relative to each other in a direction parallel to the spindle axis (the "Z" direction) and in a direction perpendicular to the spindle axis (the "X" direction), or a combination of both, so that the tool cuts into the workpiece material at a predetermined rate and the desired shape is thereby generated. A liquid coolant is provided at the point of tool contact to cool and lubricate the cutting surfaces and to help remove chips formed by the cutting operation.
In conventional turning machines, the tool is often mounted on a tool post which is mounted to the bed of the machine. In machines where it is desirable to perform a multitude of operations using various tools, a tool turret may be used which incorporates a rotatable turret having the various tools mounted thereon. A desired tool can thus be rotated into the cutting position for engagement with the workpiece.
The tool post or turret is mounted to the bed of the machine in one or more guideways, or ways, which permit linear movement of the tool relative to the headstock. In conventional machines, the tool is mounted on a cross slide which allows the tool to move in the "X" direction. The cross slide is in turn mounted on a longitudinal slide which allows the tool to move in the "Z" direction. The tool can thus be moved in the proper relationship relative to the workpiece, however, many problems inhere in such conventional configurations.
First, conventional turning machines are not fully compatible with modern automated manufacturing techniques which require automated loading and unloading of workpieces from a workpiece conveying means, such as a conveyor belt. The configuration of the headstock and tool as mounted on the bed of conventional turning machines makes it difficult to provide a conveyor belt adjacent and below the chuck. Accordingly, a workpiece loader must be used to pick-up the workpiece from the conveyor belt and place it in the chuck of the machine. In addition, a workpiece unloader may be necessary to remove the workpiece from the chuck and place it on another conveyor belt. The workpiece loader and unloader thus add greatly to the cost and complexity of the machine. Moreover, if manual loading or unloading is performed, the configuration of conventional machines makes it difficult for the operator to reach the chuck.
Second, the chips and coolant are not easily removed from the cutting area in conventional turning machines. Errant chips can mechanically damage the various components of the ways and slides. Further, the chips and coolant are often quite hot and, if not effectively transported away from the cutting area, will transfer heat to the machine. This will cause thermal expansion of the bed, ways and slides which decreases the accuracy and precision of the machine. The headstock/tool configuration of conventional machines makes it difficult to effectively transport chips and coolant away from the machine because it is difficult to provide a chip conveyor below the chuck.
One prior attempt at solving these problems is published French patent application No. 2,602,703. The publication discloses a turning machine having the headstock mounted so that it can be moved in the "X" direction so as to facilitate the loading and unloading of workpieces, and the tool carriage is movable in the "Z" direction toward and away from the headstock. The turning machine of this publication is believed to require a precise delivery of the workpiece to the headstock, and in addition, the chip and coolant removal problem is not addressed.
Accordingly, it is an object of the present invention to provide an improved turning machine which alleviates the disadvantages of the prior machines as noted above.
It is another object of the present invention to provide a turning machine which facilitates easier loading and unloading of workpieces.
It is yet another object of the present invention to provide a turning machine which facilitates better chip and coolant removal.